title: An assessment of the iPad as a testing platform for distance visual acuity in adults.
abstract: OBJECTIVE
  Visual acuity is a common measurement in general practice, and the advent of new technology such as tablet computers offers a change in the way in which these tests are delivered. The aim of this study was to assess whether measurements of distance visual acuity using LogMAR letter charts displayed on an iPad tablet computer were in agreement with standard clinical tests of visual acuity in adults with normal vision.
  
  
  METHODS
  Blinded, diagnostic test study.
  
  
  METHODS
  Single centre (University) in Auckland, New Zealand.
  
  
  METHODS
  University staff and students (n=85). Participants were required to have visual acuity better than 6/60 and wear habitual refractive correction during testing. Participants were excluded if there was any history of ocular pathology.
  
  
  METHODS
  Visual acuity measured under a number of conditions.
  
  
  RESULTS
  The iPad tablet with its glossy screen was highly susceptible to glare resulting in acuity measurements that were significantly poorer (approximately 2 LogMAR lines) than those made using an ETDRS chart and a standard computerised testing system (n=56). However, fitting the iPad with an antiglare screen and positioning the device away from sources creating reflected (veiling) glare resulted in acuity measurements that were equivalent those made using gold standard charts (n=29).
  
  
  CONCLUSIONS
  Tablet computers are an attractive option for visual acuity measurement due to portability, the ability to randomise letters, automated scoring of acuity and the ability to select from a range of charts. However, these devices are only suitable for use in situations where sources of glare can be eliminated.
authors.affiliation: Department of Optometry and Vision Science, University of Auckland, Auckland, New Zealand.
authors.forename: J M
authors.initials: JM
authors.lastname: Black
authors.forename: R J
authors.initials: RJ
authors.lastname: Jacobs
authors.forename: G
authors.initials: G
authors.lastname: Phillips
authors.forename: L
authors.initials: L
authors.lastname: Chen
authors.forename: E
authors.initials: E
authors.lastname: Tan
authors.forename: A
authors.initials: A
authors.lastname: Tran
authors.forename: B
authors.initials: B
authors.lastname: Thompson
keywords: Biotechnology & Bioinformatics; Ophthalmology